Great news! The TSA allows TENS* units!
Via Reason Magazine:
*Transcutaneous Electrical Nerve Stimulator
A TENS unit is a non-invasive, low risk nerve stimulator intended to reduce acute or chronic pain. Here’s how it works: Electrodes are stuck to your skin. The electrodes are connected to a device — which is usually small, portable (about the size of a cell phone). The unit basically generates low-level elctro-pulses to the nerves, essentially blocking/interfering with pain signals to the brain. For many people, a TENS unit can provide pain relief and comfort.
Laughter is the best medicine
…and sometimes TENS units are, too,
Timothy J. Allen, MD
Neurology Specialists of the Rockies